WordNet (r) 3.0 (2006):

pocket calculator
    n 1: a calculator small enough to hold in the hand or carry in a
         pocket [syn: hand calculator, pocket calculator]

The Free On-line Dictionary of Computing (30 December 2018):

pocket calculator

    A small battery-powered digital electronic device
   for performing simple arithmetic operations on data input on a
   keypad and outputting the result (usually a single number) to
   a simple LCD or other display.

   The most sophisticated programmable calculators are really
   pocket computers which are limited to handling numerical
   data only.

   (1996-12-23)